Chinese laser module on ramps, engraving questions July 20, 2017 03:35AM |
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Re: Chinese laser module on ramps, engraving questions July 24, 2017 04:50AM |
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Quote
finch666
The laser driver also has an analogue input.
Anyway, Im wondering what I'm doing wrong.
Should the TTL input be used for switching on and off and should the analogue input be used for variable laser power?
Re: Chinese laser module on ramps, engraving questions July 24, 2017 10:09AM |
Registered: 6 years ago Posts: 6 |
Driver had analogue input too, so I hooked up another adjustable power supply to the analogue input.Quote
cozmicray
I don't understand voltage trials
The driver circuit is 12V input
use a separate 12V power supply with enough current (amps) capacity
This should provide max laser power at continuos ON
Then TTL between 0 -5 volts to PWM the ON/OFF cycle (should keep it below 5kHz)
fan output is not TTL but just a 0 -12 volt for fan drive
Look for a TTL output on arduino
Look at the pins file for pin definition
[reprap.org]
What choices in your software is there to control laser?
Re: Chinese laser module on ramps, engraving questions July 24, 2017 10:16AM |
Registered: 6 years ago Posts: 6 |
Quote
VDX
... the cheap chinese drivers are not consistent in behaviour and quality, even if in same layout/form and from the same vendor - so not really worth to compare to a standard like "TTL" or a common 0-5V or 0-10V analogue input
Even with most comercial drivers analogue controlling is mostly not linear and has to be adjusted for the specific diode and the resulting (effective) power in relation to speed.
I'm driving all my laser-engravers and -cutters with pulsed drivers, where the resulting power is a result of pulse length and count of pulses per mm, not plain PWM.
One essential thing to look at - only use max. 95percent of the stated "safe" current with good cooling, or the diode will degrade with time ... and check the driver for eventual spikes or transients when pulsing, as this will sure kill your diode pretty fast ...
Re: Chinese laser module on ramps, engraving questions July 24, 2017 10:21AM |
Registered: 6 years ago Posts: 6 |
Quote
trapperjohn
Quote
finch666
The laser driver also has an analogue input.
Anyway, Im wondering what I'm doing wrong.
Should the TTL input be used for switching on and off and should the analogue input be used for variable laser power?
Are you sure the driver has an analogue input? It is not advertised and I can't identify it on the product images ...
I guess, it is just a simple TTL driver - i.e. you connect laser power (12V) to LD+/- and use the TTL input to connect your controller's PWM port. A "high" signal (~5V) will power the laser, a "low" signal (~0V) will switch it off. The right combination of PWM pulses and movement speed could give you the ability to run engravings with less intensity. Eventually you could use the potentiometers to reduce the laser current if you don't need the full power.